Centrifuge for the separation of mixtures of liquids

ABSTRACT

A centrifugal separator having a hermetically sealed inlet, a hermetically sealed outlet for the specifically lighter component, and a paring disc for the discharge of specifically heavier component. The feed passes downwardly into the drum through a hermetically sealed inlet tube, then downwardly to the bottom of the drum through passageways in the distributor. The passageways are in circumferentially spaced ribs. Specifically lighter liquid moves inwardly and between the ribs to along the axis of the separator and upwardly into and through a hermetically sealed outlet tube disposed within said inlet pipe. The separator is well suited for centrifuging refrigerated milk.

Waited Staes Patent [1 1 Niemeyer [415] Dec.9,1975

[75] Inventor: Heinrich Niemeyer, Oelde, Germany [73] Assignee: Wesfalia Separator AG, Oelde Westfalen, Germany [22] Filed: Dec. 6, 1973 [21] Appl. No: 422,467

[44] Published under the Trial Voluntary Protest Program on January 28, 1975 as document no.

3,765,601 10/1973 Gulley 233/28 FOREIGN PATENTS OR APPLICATIONS 70,778 9/1952 Netherlands 233/19 R 226,456 12/1924 United Kingdom 233/27 Primary ExaminerGeorge H. Krizmanich Attorney, Agent, or Firm-Burgess, Dinklage & Sprung [57] ABSTRACT A centrifugal separator having a hermetically sealed inlet, a hermetically sealed outlet for the specifically lighter component, and a paring disc for the discharge of specifically heavier component. The feed passes downwardly into the drum through a hermetically sealed inlet tube, then downwardly to the bottom of the drum through passageways in the distributor. The passageways are in circumferentially spaced ribs. Specifically lighter liquid moves inwardly and between the ribs to along the axis of the separator and upwardly into and through a hermetically sealed outlet tube disposed within said inlet pipe. The separator is well suited for centrifuging refrigerated milk.

5 Claims, 2 Drawing Figures UQS, Patent Dec. 9, 1975 CENTRIFUGE FOR THE SEPARATION OF MIXTURES OF LIQUIDS BACKGROUND The invention relates to a centrifuge for the separa tion of mixtures of liquids, with a hermetically sealed inlet leading downward into the drum for the liquid mixture to be separated, and a hermetically sealed outlet leading upwardly out of the drum for the specifically lighter component.

For the hermetic sealing of stationary inlets and outlets to the rotating drum, elastic sleeve seals are almost exclusively used, which can be disposed in the stationary or rotating part and are in frictional engagement with the other part during operation. The liquid entering and leaving provides for the necessary cooling and lubrication of these seals.

Fully hermetic and semihermetic centrifuge constructions are known.

German Pat. No. 1,094,193 discloses a fully hermetic centrifuge in which both the inlet for the liquid mixture and the two outlets for the separated components are sealed against the rotating drum. The inlet leads downwardly into the drum and the outlets lead upwardly out of the drum. The inlet pipe is centrally disposed and surrounded by the two outlets.

US. Pat. No. 2,223,999 discloses a semihermetic design. The liquid mixture is fed to the drum from below through the hollow spindle. The specifically lighter component is discharged upwardly through a hermetically sealed central discharge pipe, while the specifically heavier component is spun into a catching vessel through a regulating disk at the neck of the drum.

Hermetically sealed inlet and outlet lines have the advantage first of all that the material being centrifuged does not come in contact with the atmosphere, so that oxidation of the liquid being centrifuged is prevented.

A hermetically sealed inlet additionally has the advantage that the liquid being treated passes smoothly out of the stationary inlet line into the rotating drum, because the inlet chamber is always filled with liquid. This prevents the shattering of dispersed particles which occurs in a centrifuge having an open inlet. In centrifuges of the latter kind the entering liquid mixture collides in the non-liquid filled inlet chamber with the rapidly rotating distributor ribs which bring it to the angular velocity of the drum. The more finely divided the particles are, the poorer is the separating effect of the drum.

A hermetically sealed outlet assures a gentle transfer of the liquid or of one of the components of the liquid from the rotating drum to the stationary discharge line. In a free discharge the liquid is hurled with great violence into the catching trough surrounding the drum; in the case of discharge by means of a paring disk it is subjected to a strongly homogenizing action as a result of being pared off in a thin stratum, and of the intense turbulence in the narrow paring channels.

A centrifugal separating drum from which each liquid component is pumped by means of a paring disk into a discharge line in which a throttling member is in stalled is likewise known, for example from German Pat. No. 716,610.

In dairies the last-named type of construction is mostly used for removing the cream from raw milk which, in the usual manner of procedure, is preheated in a heater to the skimming temperature of about 40C.

is then mixed for the above-mentioned purpose with the raw milk which is also delivered cold.

The fresh raw milk is chilled to 4C by the dairy farmer because often it is not delivered to the dairy until much later. There is a desire on the part of the dairies, therefore, -to separate the milk at this temperature. The cold skim milk can then be used directly for the standardization of the raw milk to a desired fat content. This not only saves power but also simplifies dairy operations. Furthermore, the cold cream in its natural structure is especially suitable for the preparation of whipped cream.

However, neither a centrifuge with a free discharge of cream nor one equipped with two paring disks is suitable for the separation of milk. Cream with a fat content of 40 percent is very thick, and its structure is considerably damaged if it is spun out into a catching trough or stripped off by means of a paring disk.

Neither is a centrifugal separator in which the liquid to be separated is delivered through the hollow spindle suitable for cold milk separation, because the cold spindle passing through the oil bath. promotes the formation of condensate in the oil bath, thereby causing transmission damage.

THE INVENTION The invention is addressed to the problem of creating a centrifuge which is suitable especially for the separation of cold milk. It may not have an adverse effect upon the raw milk and the cream, it must permit regulation of the butterfat content during operation, and it must not produce any condensate in the oil bath.

The centrifuge of the invention is characterized in that the inlet tube for the liquid mixture is in a flowconnecting communication with passages which are disposed at equal distances from the axis of rotation in the ribs of the distributor and empty into the inlet chamber of the drum, that the discharge tube for the specifically lighter component runs outward from the center of the distributor and passes axially through the inlet tube, and that for the removal of the specifically heavier component a paring disk is provided and a throttle member is installed in the outer discharge conduit.

In the use of the centrifuge of the invention for the separation of cold milk, the raw and skim milks are treated gently, while by means of the throttle member in the skim milk discharge conduit the depth of immersion of the paring disk is varied and thus the zone of separation between cream and skim milk can be shifted. This makes it possible continuously to vary the butterfat content during operation.

Since the tube for the discharge of the cream runs from the center of the distributor, an especially high butterfat content may be achieved. The chilling of the skim milk before standardizing raw milk is no longer necessary, and a transmission damaging formation of condensate in the oil bath cannot occur.

Thus, the invention provides a centrifugal separator for separating a liquid raw material into a specifically lighter component and a specifically heavier component. The separator comprises a rotatably mounted separator drum which provides a separating chamber for the separation, and has a distributor coaxially mounted within the separating chamber for rotation with the drum. The distributor receives material to be separated at an upper level and conveys it downwardly adjacent the drum axis, and directs it radially outwardly along the bottom of the drum into the separating chamber. The distributor comprises a plurality of axially extending ribs, disposed adjacent and radially outwardly of the axis of the drum in circumferentially spaced relation. The ribs have passages therein for conveying of the raw material to the lower part of the drum. The spaces between the ribs provide free communication between the separating chamber and an axially extending center portion of the drum, for passage of specifically lighter component to said center portion of the drum. An inlet tube is mounted on the distributor for rotation therewith for conveying raw material downwardly into the drum to said passages of the ribs. A stationary inlet connector is provided for delivering of raw material to the upper end of the inlet tube. A hermetic seal is provided between the inlet tube and the stationary inlet connector. An outlet tube for specifically lighter component is mounted on the distributor for rotation therewith, for conveying specifically lighter component upwardly from the said center portion of the drum. The outlet tube is disposed coaxially within the said inlet tube. A stationary outlet connector is provided for receiving specifically lighter component from the outlet tube, and there is a hermetic seal between the outlet tube and the stationary outlet connector. A paring chamber and a paring disc are provided for removal of specifically heavier component. Means are provided communicating the paring chamber with the outer portion of the drum for receiving specifically heavier component therefrom, and a discharge line communicates with the paring disc. A throttle is mounted on said discharge line.

THE DRAWINGS An embodiment of the invention is represented in the drawing, wherein FIG. 1 is a cross-section of the upright drum with a portion of the drum adjacent the axis shown along line 11 in FIG. 2, and

FIG. 2 is a cross-section taken along line 22 of FIG. 1.

The stationary inlet tube 1 is hermetically joined by means of a sleeve seal 2 to the inlet tube 3 which rotates with the drum. The annular passage 4 is in a flowconnecting communication with passages 5 which are arranged in the ribs 6 of the distributor 7 in an array such that imbalance is not imparted to the machine, e.g., at equal distances from the axis of rotation. The passage 5 empties into the inlet chamber 8 of the drum. The ribs 6 extend between upper hub 21 and lower hub 22 of the distributor. The specifically lighter component flowing inwardly between separator plates 20 from the separating chamber 9 passes between the ribs 6 into the central portion 10 (FIG. 2) of the distributor 7 from which the discharge tube 11 runs which passes axially through the inlet tube 3 and is hermetically joined by means of a sleeve seal 12 with the stationary discharge line 13. The specifically heavier component flowing outwardly from the separating chamber 9 passes through one or more passages 14 into the paring chamber 15 from'which it is pumped by means of the paring disc 16 under pressure into the stationary discharge line 17 into which a throttle member 18 is installed.

The connection means 19 serves for the connection of a water line so that, when the contrifuge is started up, and before the raw material infeed is opened, a small amount of water may be delivered for the cooling and lubrication of the sleeve seals.

The drum itself may be of any desired type of construction, e.g., even of the self-cleaning type of construction, such as is indicated in the drawing. The drum is outfitted with solids dicharge passageways 23, and a piston valve 24.

As indicated above, the separator is well suited for centrifuging of refrigerated milk. The resulting skim milk can be added to unpasteurized whole milk for standardization, and the resulting milk can be pasteurized.

What is claimed is:

1. A centrifugal separator for separating a liquid raw material into a specifically lighter component and a specifically heavier component, comprising:

a. a rotatably mounted separator drum providing a separating chamber for the separation and having a distributor coaxially mounted therein for rotation with the drum for receiving material to be separated in the upper part of the drum and conveying it downwardly adjacent the drum axis and directly it radially outwardly adjacent the bottom of the drum,

the distributor comprising a plurality of axially extending ribs disposed adjacent and radially outwardly of the axis of the drum in circumferentially spaced relation, the ribs having passages therein for conveying of raw material to the lower part of the drum, the spaces between the ribs providing free communication between the separating chamber and an axially extending center portion of the drum for passage of specifically lighter component to said center portion of the drum,

c. an inlet tube mounted on the distributor for rotation therewith for conveying raw material downwardly into the drum to said passages of the ribs, and a stationary inlet connector for delivering of raw material to the upper end of the inlet tube, and a hermetic seal between the inlet tube and stationary inlet connector,

(I. an outlet tube for specifically lighter component mounted on the distributor for rotation therewith for conveying specifically lighter component upwardly from the said center portion of the drum, said outlet tube being disposed within said inlet tube, and a stationary outlet connector for receiving specifically ligher component from the outlet tube, and an hermetic seal between the outlet tube and stationary outlet connector,

e. a paring chamber and paring disc for removal of specifically heavier component, means communicatin g the paring chamber with the outer portion of the drum for receiving specifically heavier component therefrom, a discharge line communicating with the paring disc and a throttle in said discharge line. I

2. Centrifugal separator according to claim 1, the distributor ribs being disposed a fixed distance from the 6 4. The process of producing standardized unpasteurized milk which comprises adding skim milk produced by the process of claim 3, to the unpasteruized milk to be standardized.

5. The process of producing pasturized, standardized milk which comprises pasteurizing the standardized milk of claim 4. 

1. A centrifugal separator for separating a liquid raw material into a specifically lighter component and a specifically heavier component, comprising: a. a rotatably mounted separator drum providing a separating chamber for the separation and having a distributor coaxially mounted therein for rotation with the drum for receiving material to be separated in the upper part of the drum and conveying it downwardly adjacent the drum axis and directly it radially outwardly adjacent the bottom of the drum, b. the distributor comprising a plurality of axially extending ribs disposed adjacent and radially outwardly of the axis of the drum in circumferentially spaced relation, the ribs having passages therein for conveying of raw material to the lower part of the drum, the spaces between the ribs providing free communication between the separating chamber and an axially extending center portion of the drum for passage of specifically lighter component to said center portion of the drum, c. an inlet tube mounted on the distributor for rotation therewith for conveying raw material downwardly into the drum to said passages of the ribs, and a stationary inlet connector for delivering of raw material to the upper end of the inlet tube, and a hermetic seal between the inlet tube and stationary inlet connector, d. an outlet tube for specifically lighter component mounted on the distributor for rotation therewith for conveying specifically lighter component upwardly from the said center portion of the drum, said outlet tube being disposed within said inlet tube, and a stationary outlet connector for receiving specifically ligher component from the outlet tube, and an hermetic seal between the outlet tube and stationary outlet connector, e. a paring chamber and paring disc for removal of specifically heavier component, means communicating the paring chamber with the outer portion of the drum for receiving specifically heavier component therefrom, a discharge line communicating with the paring disc, and a throttle in said discharge line.
 2. Centrifugal separator according to claim 1, the distributor ribs being disposed a fixed distance from the axis of the drum.
 3. The process of centrifuging milk and producing skim milk and cream which comprises, with a separator according to claim 1, feeding the milk in refrigerated condition to said stationary inlet connector, centrifuging the separator, withdrawing skim milk from said stationary outlet connector, and withdrawing cream from said discharge line.
 4. The process of producing standardized unpasteurized milk which comprises adding skim milk produced by the process of claim 3, to the unpasteruized milk to be standardized.
 5. The process of producing pasturized, standardized milk which comprises pasteurizing the standardized milk of claim
 4. 